Serious Materials has raised $60 million in a third round of funding, bringing the total raised by the green building products company to over $120 million.

The company specializes in products that either cost less energy to manufacture or reduce the amount of energy a building might consume in day-to-day operations. The company's windows – which include an insulated frame and films that block solar radiation – insulate better than regular walls, thereby reducing the load on air conditioners and heaters.

Building operations consume around 39 percent of the total energy in the U.S. and construction materials gobble up another 12 percent, according to the Department of Energy. A large number of researchers and policy experts believe that greenhouse gas emissions and power consumption can be reduced more rapidly for less money through green retrofits than building solar or wind farms.

Along the way, Serious has become one of the more visible green companies in Silicon Valley and many other building material startups have emerged in its wake. Barack Obama met with CEO Kevin Surace at the White House earlier this year. Vice President Joe Biden, meanwhile, appeared at Serious events and saluted the company for purchasing defunct window factories in Illinois and Pennsylvania and rehiring many of the factory workers.

But it hasn't been one completely happy stroll to the construction supply story. EcoRock – a type of drywall created by Serious that requires very little energy to manufacture and in fact can be made in factories powered by solar panels – has yet to come to market. It is currently in testing, although it is going up in some designer homes. Serious has shown samples since early 2007. In one of the first articles on the company, Serious said it was aiming to get EcoRock out in 2008. Since then, though, Serious have emphasized the lengthy steps required to get to market.

The company has also had to spend years building up a sales channel and credibility among contractors and architects, notoriously skittish professions when it comes to new materials. Developing the channel, Surace has said, has been one of the company's biggest challenges.

While several solar companies have raised over $100 million, there are only a handful of non-solar companies that have entered the nine-figure club. The amount of money raised by Serious also reflects one of the challenges facing green building companies. Like most solar companies, green building companies make things, which means investing in factories and hiring employees.

Serious was founded by chairman Marc Porat, who, back in the 1990s, convinced then Apple CEO John Sculley to spin out General Magic as a company. Porat also incubated Zeta Communities, a modular builder that opened a factory today, and CalStar Products, a green cement maker that recently appointed Michael Kane as CEO. In a sense, he's the Elon Musk of plywood.

Investors in this round included new investors like Merisow Financial and Enertech Capital as well as returnees like New Enterprise Associates, Navitas Capital (which specializes in green building investments) Foundation Capital and Rustic Canyon Partners.